In a WLAN system involving multiple access points (AP)s, it is desirable to provide uninterrupted service when the mobility or movement of network devices, communications units, mobile phones, subscriber devices, or the like, requires a transfer of service from one AP associated with the WLAN to another. Such transfers or handovers are of particular importance for real time or time critical data, such as voice or the like, since interruptions of data traffic associated therewith might result in a degradation of quality or interruption or dropping of a voice conversation. Thus, a requirement for mobility in WLAN systems is that a traffic interruption associated with voice or other real-time data resulting from an AP-to-AP handover must be eliminated or be reduced to an insignificant amount so as not to affect the quality of, for example, a voice conversation or like real time network data transaction.
Important considerations should be made when attempting to provide WLAN mobility including: 1) additional software, e.g. Mobile-IP related software, in mobile network elements, or clients, should not be required so that terminal costs are maintained at a minimum, 2) all services associated with the WLAN should be supported, 3) the deployment of additional hardware should not be required in the WLAN, 4) manual configuration should be avoided, 5) dynamic address assignment, e.g. DHCP, should be supported, and 6) a variety of wired and wireless configurations of the WLAN should be flexibly supported. Of course, other considerations may also be important.
Problems arise however, in that many solutions available for providing mobility fail to support key considerations such as, for example, those listed above or additional considerations. For example, in conventional WLANs, APs act as bridges such that while mobility between APs on the same subnet is possible, traffic interruptions may be too long. Traffic interruptions may be worsened by the addition of, for example, 802.1x authentication or the like such as Lightweight Extensible Access Protocol (LEAP).
Thus a need exists for solutions to the mobility issues noted above and additional problems such as cost containment and the like.